One-Pot Preparation of Amine-Functionalized PDMS Elastomer Sheets Exhibiting Strong Carbon Dioxide-Induced Adhesion Switching

Abstract

CO2-responsive materials, which enable switching of properties and functions using carbon dioxide (CO2), represent a promising class of functional materials for effective CO2 utilization and have attracted significant recent attention. In this study, we demonstrate that an amine-functionalized polydimethylsiloxane elastomer sheet prepared via a one-pot process exhibits a reversible enhancement in tack (adhesion) of up to 50-fold upon exposure to CO2. Owing to the high CO2 permeability of PDMS, CO2 rapidly diffuses into the elastomer and reacts with amine groups to predominantly form ammonium carbamate. These species aggregate within the PDMS matrix to form nanodomains, leading to pronounced changes in viscoelastic properties. In particular, the increase in tack correlates with an increase in the loss tangent (tanδ). In contrast, water contact angle measurements indicate no change in surface chemical composition upon CO2 exposure. Therefore, the CO2-induced enhancement of adhesion is attributed to increased energy dissipation arising from changes in bulk viscoelasticity during debonding, rather than changes in surface chemistry.